Final answer:
The question 'Are you having a problem with driving at night?' best addresses normal physiological changes in middle adulthood, especially relating to vision decline.
Step-by-step explanation:
To determine the presence of a normal physiological change experienced by a middle-aged client, the most appropriate nursing assessment question would be “Are you having a problem with driving at night?” This question directly addresses the common age-related decline in vision that often begins during middle adulthood, which can include difficulties with night vision and can be indicative of changes such as presbyopia or early cataracts. Question options regarding teeth and gums, family history of thyroid problems, or skin-moisturizing routine might elicit information regarding health issues, but these issues are not necessarily age-specific physiological changes occurring in middle adulthood. It's important for health assessments to consider both normal aging processes as well as other health concerns that may arise.